-Data presented in a late-breaking presentation at the European Society of Cardiology (ESC) Congress 2026- -Phase 1a clinical data for CTX310® continued to demonstrate robust, dose-dependent reductions in circulating ANGPTL3 with a mean reduction from baseline of 79% (maximum 89%), a mean reduction in triglycerides (TG) of 48% (maximum 78%), and a mean reduction of low-density lipoprotein (LDL) of 53% (maximum 84%) at the highest dose- -CTX310 was well tolerated with no treatment-related serious adverse events, no ≥Grade 3 changes in liver transaminases, and no additional treatment-related adverse events since the previous update- -Findings simultaneously published in The New England Journal of Medicine entitled “Durability of CRISPR-Cas9 Gene Editing Targeting ANGPTL3 with CTX310”- ZUG, Switzerland and BOSTON, Aug. 28, 2026 (GLOBE NEWSWIRE) — CRISPR Therapeutics (Nasdaq: CRSP) today presented durability data from its Phase 1a clinical trial evaluating CTX310®, an investigational, in vivo CRISPR/Cas9 gene editing therapy targeting ANGPTL3. A single-course treatment with CTX310 produced deep and durable reductions in circulating ANGPTL3, triglycerides (TG), and low-density lipoprotein (LDL) that were sustained through one year of follow-up. At the highest dose, mean reductions from baseline were 79% (maximum 89%) for ANGPTL3, 48% (maximum 78%) for TG, and 53% (maximum 84%) for LDL. These extended follow-up data demonstrate the durability of CTX310’s effect and support its potential to deliver long-lasting lipid lowering after a single intravenous (IV) infusion. These data were presented today during a late breaking session at the European Society of Cardiology (ESC) Congress 2026 and extend the Phase 1 results previously presented. The data were also published today in The New England Journal of Medicine (NEJM) in a peer reviewed article entitled “Durability of CRISPR-Cas9 Gene Editing Targeting ANGPTL3 with CTX310.” CRISPR Therapeutics is advancing CTX310 in a Phase 1b clinical trial, with U.S. and ex-U.S. trials ongoing, and expects to provide an additional update on the CTX310 program in the second half of 2026. “These durability data mark an important next step for the CTX310 program and for the field of in vivo gene editing,” said Naimish Patel, M.D., Chief Medical Officer, CRISPR Therapeutics. “Evidence that a single dose can produce lasting lipid lowering is central to our goal of developing one-time treatments for cardiometabolic diseases. These results provide strong support for continued advancement of CTX310 and our broader cardiovascular gene editing portfolio, and we look forward to sharing new data from the severe hypertriglyceridemia cohort of the CTX310 Phase 1b trial in the second half of this year.” “For patients at high cardiovascular risk, the biggest challenge is often not starting therapy but staying on it, since daily medications require lifelong adherence that many patients are unable to maintain,” said Luke Laffin, M.D., principal investigator and Medical Director of the Cleveland Clinic Coordinating Center for Clinical Research. “A single infusion producing durable reductions at one-year is an encouraging signal that a one-time approach could help close that adherence gap.” “What is compelling about this update is that the reductions in ANGPTL3, triglycerides, and LDL from a single infusion have persisted out to one-year, suggesting a sustained biological effect,” said Steven E. Nissen, M.D., senior author of the study and Chief Academic Officer at the Cleveland Clinic Heart, Vascular and Thoracic Institute. “A one-time treatment with this degree of durability could represent a meaningful advance in how we manage lifelong lipid disorders.” Phase 1a Clinical Trial Design The Phase 1a portion of the study was an open label, dose-escalation trial evaluating single-course IV doses of CTX310 ranging from 0.1 to 0.8 mg/kg (lean body weight) targeting ANGPTL3 in four patient groups: homozygous familial hypercholesterolemia (HoFH), severe hypertriglyceridemia (sHTG), heterozygous familial hypercholesterolemia (HeFH), or mixed dyslipidemias (elevated TG and LDL). Eligible participants had uncontrolled TG levels >150 mg/dL and/or LDL cholesterol >100 mg/dL (or >70 mg/dL for those with established ASCVD) despite background standard of care per local guidelines. The majority of participants were receiving statins and/or ezetimibe, while 40% were taking PCSK9 inhibitors. The trial was designed to evaluate safety and tolerability as primary endpoints, with changes in circulating ANGPTL3 protein, TG, and LDL as secondary endpoints.   Safety and Tolerability Single-course ascending doses of CTX310 were administered to 15 participants across sequential cohorts, and all participants completed at least one-year of follow-up as of the data cutoff. CTX310 was generally well tolerated, and no dose-limiting toxicities or serious adverse events related to treatment. Adverse events were generally mild to moderate. As previously reported in Laffin et al. (2025), one participant experienced an allergic reaction that resolved the following day with supportive care. Infusion-related reactions occurred in three participants (two at 0.6 mg/kg and one at 0.8 mg/kg dose), all Grade 2. All events resolved, and all participants completed their infusions. Beyond the transient aminotransferases elevation previously reported in one participant shortly after treatment, there were no liver function test elevations throughout the remainder of the trial. The safety events described above were previously reported in Laffin et al. (New England Journal of Medicine, 2025) and reflect the initial treatment period of the Phase 1a clinical trial. No new treatment-related safety events were observed during extended follow-up. Efficacy Highlights These new results build upon previously disclosed clinical data from 15 participants across four sequential cohorts, corresponding to lean body weight-based doses of DL1 [0.1 mg/kg], DL2 [0.3 mg/kg], DL3 [0.6 mg/kg], DL3.5 [0.7 mg/kg] and DL4 [0.8 mg/kg]. All participants had at least one-year of follow-up. Dose dependent reductions in circulating ANGPTL3 protein were sustained through one-year following CTX310 infusion.Among participants treated at 0.8 mg/kg, ANGPTL3 reductions of up to 89% were observed, with a mean reduction of 79% at one-year following CTX310 infusion. Next Steps The Phase 1b portion of the trial examines a fixed flat dose regimen of CTX310 equivalent to the most efficacious dose in Phase 1a (0.8mg/kg). CRISPR Therapeutics continues to anticipate sharing an update from the CTX310 Phase 1b clinical trial in the second half of 2026, focused on severe hypertriglyceridemia patients. About In Vivo Liver Editing Programs CRISPR Therapeutics has established a proprietary lipid nanoparticle (LNP) delivery platform to enable gene editing in the liver using both CRISPR/Cas9 and its novel, proprietary SyNTase™ editing technology. The Company’s in vivo portfolio includes three cardiovascular programs: CTX310, targeting angiopoietin-related protein 3 (ANGPTL3), in development for heterozygous and homozygous familial hypercholesterolemia, mixed dyslipidemias, and severe hypertriglyceridemia; CTX340™, targeting angiotensinogen (AGT), in development for refractory hypertension; and CTX321™, targeting LPA, in development for patients with elevated lipoprotein(a) [Lp(a)]. In addition, the Company’s disclosed development candidates also include CTX460™, targeting SERPINA1 using SyNTase editing, for the treatment of alpha-1 antitrypsin deficiency (AATD). About CRISPR Therapeutics CRISPR Therapeutics is a leading biopharmaceutical company focused on developing transformative gene-based medicines for serious human diseases. Founded over a decade ago as an early pioneer in CRISPR/Cas9 gene editing, the Company has evolved from a pioneering research-stage organization into an industry leader, marking a historic milestone with the approval of CASGEVY® (exagamglogene autotemcel [exa-cel]), the world’s first CRISPR-based therapy, for eligible patients with sickle cell disease and transfusion-dependent beta thalassemia. Today, CRISPR Therapeutics is advancing a broad, diversified pipeline spanning hemoglobinopathies, cardiovascular disease, autoimmune disease, oncology, regenerative medicine and rare diseases. The Company is also expanding its gene editing toolkit through SyNTase™ editing, its novel, proprietary platform designed to enable precise, efficient, and scalable gene correction. To accelerate its impact, CRISPR Therapeutics has established strategic collaborations with leading biopharmaceutical partners, including Vertex Pharmaceuticals. CRISPR Therapeutics AG is headquartered in Zug, Switzerland, with its wholly-owned U.S. subsidiary, CRISPR Therapeutics, Inc., and R&D operations based in Boston, Massachusetts and San Francisco, California. To learn more, visit www.crisprtx.com. CRISPR THERAPEUTICS® standard character mark and design logo, CTX310®, CTX321™, CTX340™, CTX460™ and SyNTase™ are trademarks and registered trademarks of CRISPR Therapeutics AG. All other trademarks and registered trademarks are the property of their respective owners. Reference Laffin L, et al. Phase 1 Trial of CRISPR-Cas9 Gene Editing Targeting ANGPTL3. The New England Journal of Medicine. 2025. CRISPR Special Note Regarding Forward-Looking Statements Statements contained in this press release regarding matters that are not historical facts are “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995. Because such statements are subject to risks and uncertainties, actual results may differ materially from those expressed or implied by such forward-looking statements. Such statements include, but are not limited to, statements regarding any or all of the following: (i) CRISPR Therapeutics preclinical studies, clinical trials and pipeline products and programs, including, without limitation, manufacturing capabilities, status of such studies and trials, potential expansion into new indications and expectations regarding data, safety and efficacy generally; (ii) data included in the above-described oral presentation and any associated abstracts or posters, data included in the above-described article in The New England Journal of Medicine, as well as the ability to use data from ongoing and planned clinical trials for the design and initiation of further clinical trials; and (iii) the therapeutic value, development, and commercial potential of gene editing technologies and therapies, including CRISPR/Cas9 and SyNTase, as well as other technologies. Risks that contribute to the uncertain nature of the forward-looking statements include, without limitation, the risks and uncertainties discussed under the heading “Risk Factors” in CRISPR Therapeutics most recent annual report on Form 10-K and in any other subsequent filings made by CRISPR Therapeutics with the U.S. Securities and Exchange Commission. Existing and prospective investors are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date they are made. We disclaim any obligation or undertaking to update or revise any forward-looking statements contained in this press release, other than to the extent required by law. Investor Contact: +1-617-307-7503 ir@crisprtx.com Media Contact: +1-617-315-4493 media@crisprtx.com

ZUG, Switzerland and BOSTON and SAN DIEGO and SHANGHAI, Sept. 22, 2025 (GLOBE NEWSWIRE) — CRISPR Therapeutics (NASDAQ: CRSP), a biopharmaceutical company focused on creating transformative gene-based medicines for serious diseases, and Sirius Therapeutics, a clinical stage biotech company developing innovative small interfering RNA (siRNA) therapies for global markets, today announced that the first patient has been dosed in a Phase 2 clinical trial of SRSD107, a next-generation, long-acting Factor XI (FXI) siRNA for the prevention of venous thromboembolism (VTE) in patients undergoing total knee arthroplasty (TKA). SRSD107 is being co-developed by CRISPR Therapeutics and Sirius Therapeutics as part of a strategic collaboration to advance innovative treatments for cardiovascular and clotting-related diseases. “We are pleased to announce that our Phase 2 clinical trial is now underway, and the first patient has been dosed,” said Naimish Patel, M.D., Chief Medical Officer of CRISPR Therapeutics. “Until now, existing anticoagulant options have been limited by bleeding risk, frequent dosing, and complex management challenges for patients with high thrombotic risk. SRSD107 offers the potential to reduce pathological thrombosis while minimizing bleeding risk, with sustained but reversible pharmacodynamic effects and the possibility of infrequent dosing. We look forward to exploring how this differentiated approach could meaningfully improve outcomes for patients in need.” “We are very excited to announce that the first patient has been dosed in our Phase 2 trial of SRSD107, marking a significant milestone for this program,” said Patrick Yue, M.D., Chief Medical Officer of Sirius Therapeutics. “This study will evaluate clinical efficacy as proof of concept for Factor XI inhibition using our siRNA approach, building on the positive results from our Phase 1 trials, and we look forward to the progress of this trial.” The ongoing Phase 2 clinical trial is a randomized, multicenter, global study evaluating the safety and efficacy of SRSD107 for the prevention of VTE in patients undergoing TKA. The trial will assess the anticoagulant effects and pharmacological profile of SRSD107 and help inform dose selection for future pivotal studies, with the goal of confirming its potential as a differentiated approach for reducing thrombotic risk in patients. SRSD107 is designed to selectively inhibit FXI, a key driver of pathological thrombosis, with minimal impact on normal hemostasis. In prior Phase 1 clinical trials conducted in Australia and China, single doses of SRSD107 were well tolerated and demonstrated strong, sustained pharmacodynamic effects, including reductions of over 93% in FXI levels, along with more than a twofold increase in activated partial thromboplastin time (aPTT) relative to baseline. These effects were sustained, with responses maintained for up to six months post-dosing. SRSD107 has the potential to be a best-in-class FXI inhibitor, achieving deep reductions in FXI with the possibility of infrequent, semi-annual subcutaneous administration and offering reversibility not observed with other anti-FXI modalities. The addressable population includes patients with atrial fibrillation, VTE, cancer-associated thrombosis, chronic Coronary Artery Disease (CAD), chronic Peripheral Vascular Disease (PVD), end-stage renal disease requiring hemodialysis, and patients undergoing major orthopedic surgery, where bleeding risk limits existing therapies. About Thromboembolic DisordersThrombosis, or blood clot formation, is the common underlying mechanism of most cases of myocardial infarction, ischemic stroke, and venous thromboembolism. Published data in The Lancet1 estimate that thromboembolic disorders are estimated to account for approximately one in four deaths worldwide. About SRSD107SRSD107 is a novel double-stranded small interfering ribonucleic acid (siRNA), that is designed to target the human coagulation factor XI (FXI) mRNA and inhibit FXI protein expression. By modulating the intrinsic coagulation pathway, SRSD107 has the potential to provide anticoagulant and antithrombotic effects. About the CRISPR Therapeutics and Sirius Therapeutics CollaborationCRISPR Therapeutics and Sirius Therapeutics entered into a strategic collaboration in 2025 to develop and commercialize novel small interfering RNA (siRNA) therapies for thromboembolic disorders and other serious diseases. The lead program, SRSD107, is a long-acting siRNA targeting Factor XI (FXI) with the potential to offer best-in-class efficacy and safety. Under the agreement, the companies will co-develop SRSD107 and share costs and profits equally. CRISPR Therapeutics will lead commercialization in the U.S., while Sirius will lead in Greater China. The collaboration also provides CRISPR Therapeutics with the option to license up to two additional siRNA programs. This partnership expands CRISPR Therapeutics’ therapeutic portfolio into RNA-based medicines, complementing its ongoing efforts in gene editing and broadening its impact across serious and chronic diseases. For Sirius, the collaboration marks a major milestone in its mission to deliver innovative RNA-based therapies globally, leveraging deep expertise in siRNA design and delivery. About CRISPR TherapeuticsSince its inception over a decade ago, CRISPR Therapeutics has evolved from a research-stage company advancing gene editing programs into a leader that celebrated the historic approval of the first-ever CRISPR-based therapy. The Company has a diverse portfolio of product candidates across a broad range of disease areas including hemoglobinopathies, oncology, regenerative medicine, cardiovascular, autoimmune, and rare diseases. In 2018, CRISPR Therapeutics advanced the first-ever CRISPR/Cas9 gene-edited therapy into the clinic to investigate the treatment of sickle cell disease and transfusion-dependent beta thalassemia. Beginning in late 2023, CASGEVY® (exagamglogene autotemcel [exa-cel]) was approved in several countries to treat eligible patients with either of these conditions. The Nobel Prize-winning CRISPR technology has revolutionized biomedical research and represents a powerful, clinically validated approach with the potential to create a new class of potentially transformative medicines. To accelerate its efforts, CRISPR Therapeutics has formed strategic partnerships with leading companies, including Vertex Pharmaceuticals. CRISPR Therapeutics AG is headquartered in Zug, Switzerland, with its wholly-owned U.S. subsidiary, CRISPR Therapeutics, Inc., and R&D operations based in Boston, Massachusetts and San Francisco, California. To learn more, visit www.crisprtx.com. CRISPR THERAPEUTICS® standard character mark and design logo are trademarks and registered trademarks of CRISPR Therapeutics AG. CASGEVY® and the CASGEVY logo are registered trademarks of Vertex Pharmaceuticals Incorporated. All other trademarks and registered trademarks are the property of their respective owners.  About Sirius TherapeuticsSirius is a global, clinical-stage biotech company developing innovative siRNA therapies focusing on the treatment of chronic diseases. The Company’s pipeline is centered around three key franchises with mega blockbuster potential: coagulation disorders, cardiometabolic diseases, and obesity. Sirius’ most advanced investigational programs include SRSD107, a FXI inhibitor targeting the anticoagulation market, SRSD216, an inhibitor of Lp(a) synthesis intended to address atherosclerotic cardiovascular disease, and SRSD384, an INHBE inhibitor for managing obesity. Founded in 2021 by a world-class leadership team and investors, Sirius has established an innovation center in the United States and a translational medicine center in China. Sirius has raised nearly US$150 million in funding to date from OrbiMed, Creacion Ventures, Hankang Capital, Delos Capital, and BioTrack Capital. CRISPR Therapeutics Forward-Looking StatementStatements contained in this press release regarding matters that are not historical facts are “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995. Because such statements are subject to risks and uncertainties, actual results may differ materially from those expressed or implied by such forward-looking statements. Such statements include, but are not limited to, statements made by Drs. Patel and Yue in this press release, as well as regarding any or all of the following: (i) CRISPR Therapeutics’ preclinical studies, clinical trials and pipeline products and programs, including, without limitation, expectations regarding data, safety and efficacy generally; (ii) data included in this press release, as well as the ability to use data from ongoing and planned clinical trials for the design and initiation of further clinical trials; (iii) the status and clinical progress of the SRSD107 clinical program and development timelines for such program; (iv) CRISPR Therapeutics’ strategy and goals; (v) the future activities of the parties pursuant to the collaboration and the expected benefits of CRISPR Therapeutics’ collaboration with Sirius Therapeutics; and (vi) the therapeutic value, development, and commercial potential of gene editing and delivery technologies and therapies, including CRISPR/Cas9. Risks that contribute to the uncertain nature of the forward-looking statements include, without limitation, the risks and uncertainties discussed under the heading “Risk Factors” in its most recent annual report on Form 10-K and in any other subsequent filings made by CRISPR Therapeutics with the U.S. Securities and Exchange Commission. Existing and prospective investors are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date they are made. CRISPR Therapeutics disclaims any obligation or undertaking to update or revise any forward-looking statements contained in this press release, other than to the extent required by law. This press release discusses investigational therapies and is not intended to convey conclusions about efficacy or safety as to those investigational therapies or uses of such investigational therapies. There is no guarantee that any investigational therapy will successfully complete clinical development or gain approval from applicable regulatory authorities.  Sirius Therapeutics Forward Looking StatementThis press release may contain certain “forward-looking statements” which are not historical facts, but instead are predictions about future events based on Sirius Therapeutic’s current beliefs, assumptions and expectations, commonly identified by words such as “would”, “may”, “expects”, “believes”, “plans”, “intends”, “projects” and other terms with similar meaning. Although we believe that our predictions are reasonable, future events are inherently uncertain, and our actual future results or performance may be materially different from what we expect. Accordingly, you are strongly cautioned that reliance on any forward-looking statements is subject to significant known and unknown risks and uncertainties. All forward-looking statements contained herein are qualified by reference to the cautionary statements set forth in this section. All information provided in this press release is as of the date of this press release and are based on assumptions that we believe to be reasonable as of this date, and we do not undertake any obligation to update any forward-looking statement, except as required under applicable law. Investor Contact:+1-617-307-7503ir@crisprtx.com Media Contact:+1-617-315-4493media@crisprtx.com 1 Lozano R, Naghavi M, Foreman K, et al. Global and regional mortality from 235 causes of death for 20 age groups in 1990 and 2010: a systematic analysis for the Global Burden of Disease Study 2010. Lancet. 2012;380, 2095-1128.

ZUG, Switzerland and BOSTON, June 30, 2025 (GLOBE NEWSWIRE) — CRISPR Therapeutics (NASDAQ: CRSP), a biopharmaceutical company focused on creating transformative gene-based medicines for serious diseases, has been named to the fifth annual TIME 100 Most Influential Companies list. The Company was recognized in the Pioneers category for its groundbreaking work in advancing the field of gene editing.  TIME highlighted CRISPR Therapeutics’ expansion beyond its landmark success in treating sickle cell disease and beta thalassemia, noting the Company’s progress into diseases with significant unmet medical need such as cardiovascular and autoimmune diseases. This momentum reflects CRISPR Therapeutics’ broader vision to make genetic medicine more scalable and accessible for patients worldwide. “Since our founding, CRISPR Therapeutics has been driven by a mission to transform medicine through bold science and meaningful innovation,” said Samarth Kulkarni, Ph.D., Chairman and Chief Executive Officer of CRISPR Therapeutics. “We are honored to be recognized by TIME. This acknowledgement is testament to the extraordinary dedication and collaboration across our teams to pioneer the next frontier of genetic medicine and improve the lives of patients around the world.” To select the list of the world’s most influential businesses of the year, TIME editors requested nominations across sectors, surveyed its global network of contributors and correspondents around the world, and sought advice from outside experts. They evaluated each company on key factors, including impact, innovation, ambition, and success. The result is a diverse group of organizations shaping the future of business and society. About CRISPR TherapeuticsSince its inception over a decade ago, CRISPR Therapeutics has evolved from a research-stage company advancing gene editing programs into a leader that celebrated the historic approval of the first-ever CRISPR-based therapy. The Company has a diverse portfolio of product candidates across a broad range of disease areas including hemoglobinopathies, oncology, regenerative medicine, cardiovascular, autoimmune, and rare diseases. In 2018, CRISPR Therapeutics advanced the first-ever CRISPR/Cas9 gene-edited therapy into the clinic to investigate the treatment of sickle cell disease and transfusion-dependent beta thalassemia. Beginning in late 2023, CASGEVY® (exagamglogene autotemcel [exa-cel]) was approved in several countries to treat eligible patients with either of these conditions. The Nobel Prize-winning CRISPR technology has revolutionized biomedical research and represents a powerful, clinically validated approach with the potential to create a new class of potentially transformative medicines. To accelerate and expand its efforts, CRISPR Therapeutics has formed strategic partnerships with leading companies including Vertex Pharmaceuticals. CRISPR Therapeutics AG is headquartered in Zug, Switzerland, with its wholly-owned U.S. subsidiary, CRISPR Therapeutics, Inc., and R&D operations based in Boston, Massachusetts and San Francisco, California. To learn more, visit www.crisprtx.com. Investor Contact:+1-617-307-7503ir@crisprtx.com Media Contact:+1-617-315-4493media@crisprtx.com

-New Phase 1 clinical data for CTX310™ continues to demonstrate dose-dependent reductions in triglycerides (TG) and low-density lipoprotein (LDL), with peak reduction of up to 82% in TG and up to 86% in LDL, with a well-tolerated safety profile- -Complete Phase 1 data presentation for CTX310 anticipated at a medical meeting in the second half of 2025- -Data update for CTX320™, targeting the LPA gene, now expected in the first half of 2026- -Preclinical in vivo cardiovascular program CTX340™ advancing toward IND / CTA filings targeting refractory hypertension- ZUG, Switzerland and BOSTON, June 26, 2025 (GLOBE NEWSWIRE) — CRISPR Therapeutics (NASDAQ: CRSP), a biopharmaceutical company focused on creating transformative gene-based medicines for serious diseases today announced updates across its in vivo cardiovascular disease programs. These include new data for CTX310™, targeting ANGPTL3, as well as continued progress on CTX320™, targeting the LPA gene, and CTX340™, targeting the AGT gene. “CRISPR Therapeutics remains focused on executing against our strategic priorities and advancing our portfolio of innovative therapies,” said Samarth Kulkarni, Ph.D., Chairman and Chief Executive Officer of CRISPR Therapeutics. “The additional data from our ongoing Phase 1 clinical trial for CTX310 reinforces the potential of our platform to transform the treatment of serious cardiovascular diseases. We are progressing with our dose-finding study and expect to share complete data at a medical meeting in the second half of this year. For CTX320, we are continuing our dose-finding study and anticipate sharing data in the first half of 2026, reflecting a strategic decision to incorporate emerging insights from the evolving Lp(a) treatment landscape.” CTX310, targeting ANGPTL3 CTX310 targets ANGPTL3, a gene that encodes for key protein involved in the regulation of low-density lipoprotein (LDL) and triglyceride (TG) levels – both of which are recognized risk factors for atherosclerotic heart disease (ASCVD). Loss-of-function mutations in ANGPTL3 are associated with significantly reduced levels of LDL and TGs, as well as reduced risk of ASCVD, without known adverse health effects. More than 40 million patients in the U.S. alone are affected by elevated LDL, severely elevated TG or both – representing a significant unmet need and a large addressable population. CTX310 is initially focused on high-risk patients with the greatest unmet medical need and limited effective treatment options. CTX310 is in an ongoing Phase 1 first-in-human clinical trial targeting ANGPTL3 in four patient groups: homozygous familial hypercholesterolemia (HoFH), severe hypertriglyceridemia (sHTG), heterozygous familial hypercholesterolemia (HeFH), or mixed dyslipidemias (MDL). Eligible participants have levels of TG >300 mg/dL and/or LDL-C >100 mg/dL (or >70 mg/dL for subjects with ASCVD). Both LDL and TG are validated surrogate endpoints accepted by regulatory agencies.These new results build upon previously disclosed results from the first 10 patients across the first four cohorts (lean body weight-based doses of DL1 [0.1 mg/kg], DL2 [0.3 mg/kg], DL3 [0.6 mg/kg] and DL4 [0.8 mg/kg]) with at least 30 days of follow-up for each participant. As dose-range finding continues, data to date demonstrate peak reductions of up to 82% in TG and LDL reductions of up to 86% at DL4 without any clinically significant changes in liver enzymes and a safety and tolerability profile consistent with previous findings.The Company anticipates presenting the complete Phase 1 data for CTX310 at a medical meeting in the second half of 2025. CTX320™, targeting LPA CTX320 is in an ongoing Phase 1 clinical trial targeting the LPA gene in patients with elevated lipoprotein(a) [Lp(a)], a genetically determined risk factor associated with increased incidence of major adverse cardiovascular events (MACE). Elevated Lp(a) levels affect up to 20% of the global population and remains unaddressed by current therapies.The Phase 1 trial is enrolling patients and dose-finding is ongoing. An update is now expected in the first half of 2026, reflecting a strategic decision to incorporate emerging insights from the evolving Lp(a) landscape. CTX340, targeting angiotensinogen (AGT) CRISPR Therapeutics is also advancing its preclinical in vivo cardiovascular program CTX340, targeting angiotensinogen (AGT) for the treatment of refractory hypertension. CTX340 is currently progressing through IND/CTA-enabling studies. About In Vivo ProgramsCRISPR Therapeutics has established a proprietary lipid nanoparticle (LNP) platform for the delivery of CRISPR/Cas9 to the liver. The Company’s in vivo portfolio includes its lead investigational programs, CTX310 (directed towards angiopoietin-related protein 3 (ANGPTL3)) and CTX320 (directed towards LPA, the gene encoding apolipoprotein(a) (apo(a)), a major component of lipoprotein(a) [Lp(a)]). Both are validated therapeutic targets for cardiovascular disease. CTX310 and CTX320 are in ongoing clinical trials in patients with heterozygous familial hypercholesterolemia, homozygous familial hypercholesterolemia, mixed dyslipidemias, or severe hypertriglyceridemia, and in patients with elevated lipoprotein(a), respectively. In addition, the Company’s research and preclinical development candidates include CTX340 and CTX450™, targeting angiotensinogen (AGT) for refractory hypertension and 5’-aminolevulinate synthase 1 (ALAS1) for acute hepatic porphyria (AHP), respectively. About CRISPR TherapeuticsSince its inception over a decade ago, CRISPR Therapeutics has evolved from a research-stage company advancing gene editing programs into a leader that celebrated the historic approval of the first-ever CRISPR-based therapy. The Company has a diverse portfolio of product candidates across a broad range of disease areas including hemoglobinopathies, oncology, regenerative medicine, cardiovascular, autoimmune, and rare diseases. In 2018, CRISPR Therapeutics advanced the first-ever CRISPR/Cas9 gene-edited therapy into the clinic to investigate the treatment of sickle cell disease and transfusion-dependent beta thalassemia. Beginning in late 2023, CASGEVY® (exagamglogene autotemcel [exa-cel]) was approved in several countries to treat eligible patients with either of these conditions. The Nobel Prize-winning CRISPR technology has revolutionized biomedical research and represents a powerful, clinically validated approach with the potential to create a new class of potentially transformative medicines. To accelerate and expand its efforts, CRISPR Therapeutics has formed strategic partnerships with leading companies including Vertex Pharmaceuticals. CRISPR Therapeutics AG is headquartered in Zug, Switzerland, with its wholly-owned U.S. subsidiary, CRISPR Therapeutics, Inc., and R&D operations based in Boston, Massachusetts and San Francisco, California. To learn more, visit www.crisprtx.com. CRISPR THERAPEUTICS® standard character mark and design logo CTX310™, CTX320™, CTX340™ and CTX450™ are trademarks and registered trademarks of CRISPR Therapeutics AG. CASGEVY® and the CASGEVY logo are registered trademarks of Vertex Pharmaceuticals Incorporated. All other trademarks and registered trademarks are the property of their respective owners. CRISPR Special Note Regarding Forward-Looking Statements Statements contained in this press release regarding matters that are not historical facts are “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995. Because such statements are subject to risks and uncertainties, actual results may differ materially from those expressed or implied by such forward-looking statements. Such statements include, but are not limited to, statements made by Dr. Kulkarni in this press release, as well as regarding any or all of the following: (i) CRISPR Therapeutics preclinical studies, clinical trials and pipeline products and programs, including, without limitation, status of such studies and trials (including guidance) and expectations regarding data, safety and efficacy generally; (ii) data included in this press release, as well as the ability to use data from ongoing and planned clinical trials for the design and initiation of further clinical trials; (iii) regulatory submissions and authorizations, including related timelines; and (iv) the therapeutic value, development, and commercial potential of gene editing and delivery technologies and therapies, including CRISPR/Cas9. Risks that contribute to the uncertain nature of the forward-looking statements include, without limitation, the risks and uncertainties discussed under the heading “Risk Factors” in its most recent annual report on Form 10-K and in any other subsequent filings made by CRISPR Therapeutics with the U.S. Securities and Exchange Commission. Existing and prospective investors are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date they are made. The Company disclaims any obligation or undertaking to update or revise any forward-looking statements contained in this press release, other than to the extent required by law. This press release also contains information regarding our industry, our business and the markets for certain of our product candidates, including data regarding the estimated size of those markets, and the incidence and prevalence of certain medical conditions. Unless otherwise expressly stated, we obtained this industry, business, market and other data from market research firms and other third parties, including medical publications, government data and similar sources. Information that is based on estimates, forecasts, projections, market research or similar methodologies is inherently subject to uncertainties and actual events or circumstances may differ materially from events and circumstances reflected in this information. This press release discusses CRISPR/Cas9 gene editing investigational therapies and is not intended to convey conclusions about efficacy or safety as to those investigational therapies or uses of such investigational therapies. There is no guarantee that any investigational therapy will successfully complete clinical development or gain approval from applicable regulatory authorities. Investor Contact:+1-617-307-7503ir@crisprtx.com Media Contact:+1-617-315-4493media@crisprtx.com